Characterization and catalytic activity of os/bentonite catalyst for hydrogenolysis of glycerol = Pencirian dan aktiviti pemangkin os/bentonit untuk tindak balas hidrogenolisis gliserol

In this study, osmium catalysts (Os/Bentonite, Os/TiO2 ) and ruthenium catalysts (Ru/Bentonite, Ru/TiO2 ) with 5% wt/wt metal loading were prepared using impregnation method and applied to convert glycerol, a renewable feedstock, to value-added chemical, 1,2-propanediol. Among these catalysts, the bentonite supported Os catalyst showed high performance with conversion and selectivity to 1,2-propanediol which were 63.3% and 82.7%, respectively. Catalytic performances of these catalysts were evaluated in glycerol hydrogenolysis using stainless steel autoclave reactor equipped with a magnetic stirrer at 150 C, hydrogen pressure 20 - 40 bar for 7 hours reaction. The effect of glycerol concentration and reaction temperature were investigated to obtain optimum conditions due to glycerol conversion and products selectivity greatly depend on these factors. Experimental results show that hydrogenolysis of glycerol at 160 C reaction temperature and 5% glycerol concentration gives a conversion of glycerol up to 100.0% with 82.9% selectivity of 1,2-propandiol. This study showed that bentonite which is cheap and abundant clay is potentially a good catalyst support material. The Os/bentonite catalyst was characterized by Temperature Programmed Reduction (TPR), nitrogen adsorption-desorption analysis (BET), Temperature Programmed Desorption-Ammonia(TPD-NH3 ) for obtaining some physicochemical properties of the catalysts. ******************************************************************************* Dalam kajian ini, pemangkin osmium (Os/bentonit, Os/TiO2 ) dan pemangkin ruthenium (Ru/bentonite, Ru/TiO2 ) dengan muatan logam 5% wt/wt disediakan dengan menggunakan kaedah impregnasi dan diaplikasikan kepada penukaran gliserol yang merupakan bahan mentah yang boleh diperbaharui kepada bahan kimia yang bernilai tinggi iaitu 1,2-propanadiol. Antara pemangkin yang dikaji, Os berpenyokong bentonit menunjukkan sifat pemangkin yang baik dengan nilai peratus penukaran dan pemilihan masing-masing adalah 63.3% dan 82.7%. Aktiviti pemangkin diuji dalam tindak balas hidrogenolisi gliserol menggunakan reaktor autoklaf tahan karat yang dilengkapi dengan pengacau magnetik pada suhu 150 ⁰C, tekanan hidrogen 20- 40 bar selama 7 jam. Kesan kepekatan gliserol dan suhu tindak balas didapati memberi kesan signifikasi terhadap peratus penukaran gliserol dan pemilihan produk. Keputusan kajian menunjukkan bahawa keadaan optimum pada suhu 160 ⁰C dan kepekatan gliserol 5% (wt/wt) memberikan penukaran gliserol sehingga 90.0% dengan peratus pemilihan terhadap 1,2- propanadiol 82.9%. Kajian ini menunjukkan bahawa bentonit yang merupakan tanah liat murah dan mudah didapati adalah berpotensi digunakan sebagai penyokong mangkin. Pemangkin Os/bentonit dicirikan menggunakan suhu pemprograman penurunan (TPR), analisis jerapan-nyahjerapan nitrogen (BET), suhu pemprograman nyahjerapan ammonia (TPD-NH3) bagi mendapatkan maklumat mengenai sifat fizikal dan kimia pemangkin

Extraction and characterization of microfibrillated and nanofibrillated cellulose from office paper waste = Pengekstrakan dan pencirian mikrofibril dan nanofibril selulosa daripada sisa kertas pejabat

The tremendous increase in papermaking and cellulose production, both of which are sourced from wood pulp, has resulted in the severe exploitation of trees, thereby leading to environmental problems, including deforestation. Besides, the reduction of paper usage is not on the horizon. Thus, when it comes to the environmental issue, the extraction of cellulose from paper waste can be an alternative initiative to mitigate the negative impact of deforestation via the reuse of paper waste. In this study, the extraction of cellulose microfibres and nanofibres was achieved through the use of office paper waste as the source material. Alkali and bleaching treatments were employed for the extraction of cellulose fibres, followed by acid hydrolysis under controlled conditions for the isolation of the cellulose nanofibres. The alkali treatment was carried out using various concentrations of 2%, 4%, 8% and 16% of sodium hydroxide (NaOH) solution, while the bleaching treatment was carried out using sodium hypochlorite (NaClO) solution. The extraction of nano-fibrillated cellulose was achieved by means of acid hydrolysis with various concentrations of 5%, 15%, 30% and 60% sulphuric acid (H2SO4 ) under controlled conditions. The structural and functional groups were analysed using attenuated total reflection Fourier transform infra-red (ATR-FTIR) imaging, while a morphological analysis was performed using optical microscopy and transmission electron microscopy (TEM). The FTIR analysis indicated that the lignin, ink, fillers and other components had been removed after the alkali and bleaching treatments. The imaging analysis using an optical microscope showed that the extracted cellulose had a fibrous and rod-like structure, while the TEM images showed that the extracted cellulose ranged from micro to nano size down to ~20-30 nm depending on the concentration of acid used. The extraction of either micro-fibrillated or nano-fibrillated cellulose from office paper waste in this work might pave the way towards the alternative reuse of office paper waste for the production and application of cellulose materials. ************************************************************************ Peningkatan besar dalam penghasilan kertas dan selulosa, di mana kedua-dua sumber berasal dari pulpa kayu telah menyebabkan eksploitasi hutan yang teruk membawa masalah alam sekitar, iaitu penebangan hutan. Selain itu, pengurangan penggunaan kertas agak tidak seimbang. Oleh itu, berhubung dengan isu alam sekitar, pengambilan selulosa dari sisa kertas boleh menjadi inisiatif alternatif untuk mengurangkan kesan negatif melalui kitar semula sisa kertas. Dalam kajian ini, pengekstrakan selulosa mikrofibril dan nanofibril telah dicapai menggunakan bahan buangan kertas sebagai sumber. Rawatan alkali dan pelunturan digunakan untuk pengestrakan serat selulosa diikuti oleh kaedah hidrolisis asid yang terkawal untuk pengasingan selulosa nanofibril. Rawatan alkali dijalankan menggunakan pelbagai kepekatan 2%, 4%, 8% dan 16% natrium hidroksida (NaOH) manakala rawatan pelunturan dilakukan dengan menggunakan larutan natrium hipoklorit (NaClO). Pengekstrakan selulosa nanofibril dicapai dengan menggunakan kaedah hidrolisis asid yang terkawal dengan pelbagai kepekatan 5%, 15%, 30% dan 60% asid sulfurik (H2SO4 ). Analisa kumpulan struktur dan fungsi dianalisis dengan menggunakan pantulan keseluruhan dikecilkan spektroskopi infra-merah transformasi Fourier (ATR-FTIR) manakala pengimejan dan analisis morfologi diperiksa menggunakan mikroskop optik dan mikroskop elektron transmisi (TEM). Analisis FTIR menunjukkan lignin, dakwat, pengisi dan komponen lain dikeluarkan selepas rawatan alkali dan pelunturan. Analisa pengimejan menggunakan mikroskop optik menunjukkan struktur berserat dan rod seperti selulosa dapat diekstrak manakala imej TEM menunjukkan saiz selulosa yang diekstrak dari mikro ke saiz nano hingga ~20-30 nm bergantung kepada kepekatan asid yang digunakan. Pengekstrakan selulosa microfibril atau nanofibril dari sisa kertas pejabat dalam kajian ini mungkin membuka jalan ke arah penggunaan semula sisa kertas pejabat dalam pengeluaran dan aplikasi bahan selulosa

Glycerol degradation in the absence of external hydrogen gas by using waste eggshell as heterogeneous catalyst = Degradasi gliserol tanpa kehadiran hidrogen luaran dengan menggunakan sisa kulit telur sebagai mangkin heterogen

The demand of biodiesel production nowadays is increasing every day. However, the booming of biodiesel demand resulted in the increase of glycerol production as a major by-product. Although glycerol could serve in various industries, the demand and usage are still limited. Therefore, an alternative method was proposed in this research in order to convert glycerol into more value-added chemicals such as methanol (MeOH), propanol (1-PrOH), and 1,2-propanediol (1,2-PDO) through a new low cost and simple approach which is the reflux technique in the absence of external hydrogen gas. Due to the concern of global food waste issues, calcium oxide (CaO) catalyst derived from waste eggshells is utilized as a possible heterogeneous catalyst. This preliminary research studied the influence of reaction temperature and reaction time whereas catalyst weight and glycerol concentration were fixed as independent variables. Overall, the three chemicals were successfully synthesized with different optimum conditions. The formation of 1,2-PDO is more preferred at lower temperature (130 °C and 5 hours) with glycerol conversion and selectivity of 53.70% and 64.76%, respectively. However, the formation of MeOH and 1-PrOH are preferred at higher temperature. The formation of 1-PrOH (170 °C and 5 hours) resulted in glycerol conversion and selectivity of 81.64% and 70.85%, respectively. Meanwhile, the best condition in the formation of MeOH is at 190 °C and 7 hours reaction time with glycerol conversion and selectivity of 65.8 % and 46.44%, respectively. ****************************************************************************** Permintaan pengeluaran biodiesel semakin meningkat setiap hari. Fungsi biodiesel itu sendiri sebagai bahan api alternatif untuk menggantikan penggunaan bahan api fosil adalah salah satu teknik terbaik untuk mengurangkan pembebasan gas karbon dioksida (CO2 ) yang dikeluarkan di atmosfera. Walau bagaimanapun, permintaan biodiesel yang tinggi menyebabkan peningkatan penghasilan gliserol sebagai produk sampingan utama. Walaupun gliserol boleh digunakan dalam pelbagai industri, permintaan dan penggunaannya masih terhad. Oleh itu, satu alternatif telah diambil dalam penyelidikan ini untuk menukar gliserol menjadi bahan kimia yang lebih bernilai seperti metanol (MeOH), propanol (PrOH) dan 1,2-propanediol (1,2-PDO) melalui pendekatan baharu yang lebih murah dan lebih mudah iaitu dengan menggunakan teknik refluks. Penukaran gliserol juga dilakukan tanpa kehadiran gas hidrogen luaran. Dengan mengambil kira mengenai isu kenaikan sisa makanan global, mangkin kalsium oksida (CaO) yang diperoleh daripada sisa kulit telur telah digunakan sebagai mangkin heterogen. Penyelidikan awal ini bertumpu mengkaji parameter pengaruh suhu tindak balas dan masa tindak balas, manakala berat mangkin dan kepekatan gliserol dijadikan sebagai pemboleh ubah tidak bersandar. Secara keseluruhan, ketiga-tiga bahan kimia telah berjaya disintesis dengan keadaan optimum yang berbeza. Pembentukan 1,2-PDO lebih baik pada suhu yang rendah (130 °C dan 5 jam) dengan penukaran gliserol dan selektiviti pada 53.70% dan 64.76%. Walau bagaimanapun, penghasilan MeOH dan 1-PrOH lebih baik pada suhu yang lebih tinggi. Penghasilan 1-PrOH (170 °C dan 5 jam) mencatatkan penukaran gliserol pada 81.64% dan selektiviti pada 70.85%. Sementara itu, keadaan terbaik dalam pembentukan metanol adalah pada 190 °C, dan masa reaksi 7 jam dengan penukaran gliserol pada 65.87% dan selektiviti produk masing-masing 46.44%

The influence of calcination temperature on iron oxide (α-Fe2O3) towards CO2 adsorption prepared by simple mixing method = Kesan suhu pengkalsinan ferum oksida (α-Fe2O3) disediakan melalui kaedah campuran ringkas terhadap penjerapan CO2

Synthesized iron oxide, α-Fe2O3 used for CO2 capturing was prepared by a simple mixing method and calcined at temperatures in a range of 350 – 850 °C. CO2 adsorption isotherms at 25 °C and 1 atm found that the sample namely s450 that calcined at 450 °C gave the highest CO2 adsorption activity with the adsorption capacity of 17.0 mgCO2/gadsorbent. Monodentate carbonate, bidentate carbonate and bicarbonates formation were observed on s450 through the IR spectra. The basicity of s450 was identified by chemisorption of CO-TPD which contains weak, medium and strong basic sites with CO total adsorbed amount of 1.99 cm3/g. It was found that s450 calcined at 450 °C has certain crystallite peaks that abruptly increased through the XRD diffractogram. The texture properties of s450 generated high porosity and more uniform sphere shape particle size with high surface area (50.5 m2/g). Furthermore, it is composed of trimodal distribution for pore size distribution curve desirable for CO2 adsorption. Penjerapan CO2 terhadap ferum oksida, α-Fe2O3 yang disintesis melalui kaedah campuran ringkas dan dikalsin pada suhu 350- 850 °C. Penjerapan isoterma CO2 pada suhu bilik, 25 °C and 1 atm mendapati sampel s450 yang dikalsin pada suhu 450 °C menunjukkan aktiviti penjerapan CO2 paling tinggi dengan keupayaan penjerapan sebanyak 17.0 mgCO2/gpenjerap. Spektrum IR telah membuktikan pembentukan spesis monodentat karbonat, bidentat karbonat dan bikarbonat pada s450. Sifat bes s450 yang dikenalpasti menggunakan jerapan kimia CO-TPD dimana jumlah CO yang dijerap oleh tapak bes lemah, sederhana dan kuat adalah 1.99 cm3 /g. Difraktogram XRD pula menunjukkan terdapat beberapa puncak kekisi yang meningkat. Tekstur s450 pula mempunyai keporosan yang tinggi dan bentuk sfera yang lebih sekata serta luas permukaan yang tinggi (50.5 m2 /g). Tambahan lagi, graf taburan saiz liang s450 juga terdiri daripada taburan jenis trimodal yang menjadi salah satu faktor penting dalam penjerapan CO

Palladium nanoparticles supported on fluorine-doped tin oxide as an efficient heterogeneous catalyst for Suzuki coupling and 4-nitrophenol reduction

Immobilization of palladium nanoparticles onto the fluorine-doped tin oxide (FTO) as support Pd/FTO, resulted in a highly active heterogeneous catalyst for Suzuki-Miyaura cross-coupling reactions and 4-nitrophenol reduction. The Pd/FTO catalyst has been synthesized by immobilization of palladium nanoparticles onto FTO via a simple impregnation method. ICP-MS analysis confirmed that there is 0.11 mmol/g of palladium was loaded successfully on FTO support. The crystallinity, morphologies, compositions and surface properties of Pd/FTO were fully characterized by various techniques. It was further examined for its catalytic activity and robustness in Suzuki coupling reaction with different aryl halides and solvents. The yields obtained from Suzuki coupling reactions were basically over 80%. The prepared catalyst was also tested on mild reaction such as reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Pd/FTO catalyst exhibited high catalytic activity towards 4-NP reduction with a rate constant of 1.776 min(-1) and turnover frequency (TOF) value of 29.1 hr(-1). The findings revealed that Pd/FTO also maintained its high stability for five consecutive runs in Suzuki reactions and 4-NP reductions. The catalyst showed excellent catalytic activities by using a small amount of Pd/FTO for the Suzuki coupling reaction and 4-NP reduction

Structural, optical and electrical properties of fluorine doped tin oxide thin films deposited using inkjet printing technique

This paper reports on structural, optical transmittance and electrical properties of fluorine-doped tin oxide (FTO) thin films deposited using an inkjet printer. The FTO ink was synthesized from a mixture of tin chloride pentahydrate (SnCl4.5H2O) and ammonium fluoride (NH4F) solutions. The thin films were deposited on glass substrates at ambient temperature or heated at 40oC and 60oC. The surface electronic state and the elemental composition of the thin films were analyzed using XPS spectroscopy. The spectra of the FTO thin films revealed that tin, oxygen, fluoride and carbon were present in the samples. The signals corresponding to Sn 3d5/2, O1s, and F1s were found at 486.6 eV, 530.5 eV and 684.5 eV, respectively. XRD analysis showed that the FTO films were in the form of crystalline with cassiterite shape. The optical and electrical properties of the films were affected by the deposition temperatures. It was observed the film deposited at 40oC has the optimum optical transmittance and sheet resistivity which were 91%T and 16 Ω/, respectively

Influence of the calcination temperature on the catalytic properties of Os/bentonite for glycerol hydrogenolysis

Selective catalytic hydrogenolysis of glycerol on Os/bentonite catalyst represents a low cost and green route for 1,2-propanediol which is major community chemical used in the production of antifreeze functional fluids, paints and humectants. The experimental results combined with the characterization studies using TPR, FESEM-EDX and XPS techniques revealed that the optimum calcination temperature was 300 °C with glycerol conversion obtained was 80.7%. This might be due to the presence of Os metal species as an active site with binding energy(BE) of Os 4f at 51.2 eV in XPS analysis. TPR profile also shows two obvious peak at reduction temperature of 95 °C and 140 °C represent for Os3+ and Os4+ species respectively. The presence of Os3+ and Os4+ species were also confirmed by XPS analysis

Effect of metals compatibility on fluorine-doped tin oxide catalyst for glycerol conversion to 1,2-Propanediol

The effect of metals on support material fluorine-doped tin oxide (FTO), were studied. A series of metals such as ruthenium (Ru), osmium (Os), palladium (Pd), and copper (Cu) on FTO support were prepared by a simple wet mixture method, and attempted as a heterogeneous catalyst to enhance the hydrogenolysis of glycerol converted to 1,2-propanediol (1,2-PDO). The physicochemical properties of the catalysts were characterized by XRD, XPS, BET, FESEM, TEM, TPR, and TPD techniques. In particular, the catalyst of Ru-FTO was recorded as a good catalyst with an optimum glycerol conversion of 100% and 1,2-PDO selectivity of 94% respectively. It was suggesting that the acid an basic properties of the catalyst could achieved the C-O and C-H bond dissociation by formation of different intermediates of acetol and acetaldehyde to become 1,2-PDO. Despite that, some reaction parameters were evaluated and optimized reaction condition were establishe

Controlled release electrochemical synthesis and cytotoxicity study of copper(II) nanoparticles in copper(II) decanoate complex

In the present study, a controlled release electrochemical (CRE) technique based on the controlled release of Cu2+ ion from Cu anode in the presence of decanoic acid (HDe) has been used to synthesize Cu(II) decanoate (CuDe2) complex. The effect of applied voltages (1–10V) and electrolyte concentrations (0.1–2.0M CH3COONH4) during the electrolysis on the nanoparticles obtained was studied using TEM. The results reveal that small-sized nanoparticles (2±1nm) were obtained by using lowest applied voltage and CH3COONH4 concentration (1V and 0.1M, respectively). The smallest nanoparticle obtained was then used in the cytotoxicity study against A549 and HeLa cells. The synthesized complex gives moderate cytotoxic effect on the selected cells (IC50=15.85μM and 20.89μM, respectively) and low cytotoxic effect on normal cells (IMR90). Apoptosis is the mode of cell death based on the apoptosis assay that has been conducted

Extraction and characterization of microfibrillated and nanofibrillated cellulose from office paper waste

The tremendous increased in papermaking and cellulose production, which both sources from wood pulp has resulted in severe exploitation of trees, leading to environmental problems, the deforestation. Besides, the reduction of paper usage is rather not in the horizon. Thus, concerning with the environmental issue, the extraction of cellulose from the paper waste can be an alternative initiative to mitigate the negative impact via reusability of paper waste. In this study, the extraction of cellulose microfibers and nanofibers were achieved using office paper waste as the source material. Alkali and bleaching treatments were employed for the extraction of cellulose fibers followed by controlled-conditions of acid hydrolysis for the isolation of the cellulose nanofibers. The alkali treatment was carried out using various concentrations of 2%, 4%, 8% and 16% of sodium hydroxide (NaOH) solution while the bleaching treatment was carried out using sodium hypochlorite (NaClO) solution. The extraction of nanofibrillated cellulose was achieved using controlled-conditions of acid hydrolysis treatment with various concentrations of 5%, 15%, 30% and 60% sulphuric acid (H2SO4). Structural and functional groups analysis was analyzed using Attenuated Total Reflection Fourier Transform Infra-Red (ATR-FTIR) while imaging and morphological analysis was examined using optical microscopy and transmission electron microscopy (TEM). FTIR analysis indicated the lignin, ink, fillers and other components were removed after alkali and bleaching treatments. Imaging analysis using optical microscope showed a fibrous and rod-like structure of the extracted cellulose while TEM images showed that the size of the cellulose extracted range from micro to nano size down to ~20-30 nm depending on the concentration of acid used. The extraction of either microfibrillated or nanofibrillated cellulose from office paper waste in this work might paves the way toward alternative reuse of office paper waste in cellulose materials production and applicatio